Reference for Bekhorot 12:24

מאי שנא מהא דתניא

But according to him who says [that the reason why there is no menstruation period while nursing is] because her limbs become disjointed<span class="x" onmousemove="('comment',' On account of the labor of childbirth.');">¹¹</span>

Jastrow

Jastrow